Dissertation style varies widely from field to field - describing an experiment in organic chemistry is obviously going to look pretty different from a study of Shakespearean plays. In general, though, there are a few key sections that any dissertation will need in order to be complete.

Abstract

An abstract is a 100-500 word paragraph that summarizes your research. The structure of the abstract should mirror the structure of your paper - there should be a few sentences of introduction and background, one or two sentences of results, and two to three sentences discussing your conclusions. The abstract is the first, and often only, section potential readers will encounter, so take the time to craft this research summary carefully.

Introduction

The main body of the dissertation starts with the introduction. This section provides the reader with some of the background information needed to understand your research and also provides an overview of what you've set out to accomplished. Start by exploring a broad view of the issues in your field, then narrow the focus to the particular subject you plan to address. Also make sure to be clear if there are any related topics your paper is NOT going to be covering: you can't address everything, so let the reader know what to expect up front.

Questions that should be answered in your introduction:

Why is this topic important?

How does the focus of your dissertation relate to larger issues in your field?

What gaps in knowledge will your research address?

What were your predictions/hypothesis going in?

Depending on the style of the dissertation you may also want to walk the reader through the organization of your chapters. This can be particularly important when writing in the humanities, since you'll have much more leeway in how you organize your ideas, and you want readers to know what to expect as they move through the paper.

The introduction will usually be much shorter than other parts of your paper and should be clear and concise. Stay away from jargon or other terms that require long explanations and avoid cluttering the section with citations. Instead, focus on your own words and ideas. It's often a good idea to also include one or two sentences that clearly summarize the goal of your research.

It's important to use the introduction to capture your audience's attention - when they reach the end of the introduction, readers should be convinced that the research you're doing is necessary and important.

Literature Review

The literature review is where you do the heavy lifting when it comes to providing background for your readers. In this section you'll use primary sources to spell out in detail the research that's already been done in your field and explain how your own effort fits within this framework. It shouldn't just be a list of sources, however. Instead, you want to use the work of others to clearly frame the prevailing theories, competing positions, and accepted methodology related to your work. There are several ways you can organize the literature review:

Chronologically. Go through the literature chronologically if you want to provide perspective on the historical development of an issue.

Thematically. If your dissertation is addressing several related concepts it can be useful to organize the literature review around particular theories or ideas.

Methodological. You can also divide the literature into sections based on research methodology. This method isn't as common and is mostly used when doing a meta-analysis or when your work explicitly addresses methodological issues.

Keep in mind that this section should not be a review of all the research you've looked at over the course of your work, but should instead focus only on the documents that are specifically related to the material covered in the body of your paper.

Methodology

No matter what field you're working in, your dissertation will need to tell the reader how you went about collecting data. This section should include an explanation of how you arrived at your chosen method of study (i.e., why are you using a particular type of experiment, a focus group, surveys, etc.) and how the study was designed.

For dissertations in the sciences, the methodology section will be a detailed, step-by-step description of the research process, including the equipment used, how measurements were taken, and the method of data analysis. After reading the methodology, a reader should know everything needed to accurately recreate your work.

If your dissertation is in the social sciences, the methodology needs to provide examples of questionnaires or other empirical data collection methods. You will also need to explain how the questions were developed and your reasons for choosing these particular tools.

For papers in the humanities the methodology section is usually shortened or omitted altogether. When included, it is commonly used to discuss the theoretical approach used by the author to analyze texts.

Results

The results section is where you present the product of your work. This is not the place to analyze the data, however. Instead it should be a simple presentation of the information you collected. Data should be aggregated into tables or figures - never just present a list of raw numbers in your paper - and the result of any statistical analysis should also be included here. Again, the results section should be free from spin or interpretation; your data should be provided independent of the wider context of the paper.

Discussion

For almost any dissertation the discussion will be the real meat of the paper. It's where you have the chance to provide your interpretation of the information you've collected and to make an argument in favor of your position. You want to present your conclusions and discuss in detail how your work led you to that position - there should be a direct line drawn from the information in the results section to your final conclusions. Once the conclusion is firmly stated, it's important to discuss how strong or weak it is. It can be tempting to exaggerate or overstate your conclusion in order to make the work seem important, but a good dissertation will address problems or limitations in the research.

The discussion is also the place to establish how your findings contribute to broader issues in your field. Refer back to the information provided in the introduction and literature review to demonstrate how your work fits within this larger framework. Lastly, take the time to explore new questions and avenues of research suggested by your findings. And remember, no new information should be presented in the discussion - this section should focus solely on analyzing information that you've already provided in the paper.

Questions that should be answered in your discussion:

What conclusions can you draw from your findings?

How do your findings relate to your chosen topic and to your field at large?

What problems/limitations did you encounter in your study?

What further avenues of research do your findings suggest?

Other dissertations styles

While these chapter headings will fit the requirements for many dissertations, every field will have its own requirements for how you organize your paper.

Humanities

Papers in Philosophy, History, English, and other humanities disciplines require an abstract, introduction, literature review, and discussion, but generally do not require a results section. Instead, the bulk of the paper will be structured to fit your argument, and chapters within the discussion should be divided to best highlight the logical progression of your work. For example, a short dissertation might have a chapter explaining theoretical models and a chapter explaining how that model relates to a particular text. Longer dissertations might be structured as a kind of point-counterpoint, where the author raises a topic, presents an theory, offers possible objections to this theory, and refutes those competing ideas.

No matter the topic, the chapter structure should make it easy for the reader to follow the development of your argument. It can also be helpful to provide a general outline for your dissertation in the introduction so that readers will know what to expect.

Engineering

Because engineering often combines real-world experimentation with conceptual modeling, dissertations in these fields may require a chapter in which the author presents a conceptual model based on his work and discusses its accuracy. This section - titled something like Theoretical Modeling - should follow the results and discussion, and the paper should end with a conclusion that ties together the practical and theoretical aspects of the work.

Social and hard sciences

Dissertation in the social and hard sciences will usually closely follow the chapter structure given above.

Remember, this is just a general outline. Depending on the length of your dissertation, these general sections will likely be broken down into several chapters. For example, if your dissertation covers multiple interconnected experiments, the methodology section might require more than one chapter. Similarly, the discussion might have separate chapters or subheadings for conclusions and further research suggestions. Also keep in mind that most schools have strict rules for dissertation structure and formatting, so before you start to write make sure you know the specific guidelines you'll need to follow.